The field of the disclosure relates generally to hat stringer fittings, and, more particularly, to a closeout fitting for a hat stringer that includes a trimmed end.
At least some known structures, such as aircraft, include structural components that are stiffened with hat stringers. At least some such hat stringers are trimmed proximate an end of the hat stringer, sometimes referred to as a “run-out” trim. For example, a run-out trim may be necessary to accommodate a structural joint fitting with another structural component. However, such a run-out trim may decrease a capability of at least some known hat stringers to carry certain loads to which the hat stringer may be subjected, such as, but not limited to, torsional loads on the hat stringer and shear loads in a cap of the hat stringer. As a result, adverse effects, such as, but not limited to, excessive hat stringer web bending and excessive localized loads on the hat stringer noodle, such as bending, torsion, shear, axial, vertical, and/or transverse localized noodle loads, may cause a crack or delamination near the run-out trim location.
Moreover, at least some known structural components include hat stringers that additionally or alternatively provide a vent path for a fluid, such as but not limited to an aircraft fuel and/or fuel vapor, associated with the structural component. To accommodate a vent system connection, an additional hole must be drilled through at least some such hat stringers at a location away from the run-out trim. However, such an additional hole may decrease a structural integrity of at least some known hat stringers. In addition, for at least some known hat stringers, a number of tasks must be performed to seal the vent path proximate a run-out trim as part of a larger process of coupling the structural component, for example an aircraft wing, to another structural component, for example an aircraft fuselage. Thus a time and a cost of the larger process is increased.